The present invention relates to a benzyl ether compound which is useful as an intermediate compound of a 1,2,4-triazole-3-carboxamide compound having a weed killing effect (herbicidal effect) and a process for producing the same. More particularly, the present invention relates to a benzyl ether compound which is used as an intermediate compound of a 1,2,4-triazole-3-carboxamide compound which is an active ingredient of a herbicide, and which is represented by the general formula (I): ##STR2## wherein R represents a branched alkyl group of 4 to 8 carbon atoms, a cycloalkyl group of 4 to 8 carbon atoms, an alkyl group of 1 to 3 carbon atoms having an alicyclic group of 3 to 7 carbon atoms, an aralkyl group of 7 to 9 carbon atoms, an alkyl group of 2 to 4 carbon atoms having an alkoxy group of 1 to 4 carbon atoms, an unsaturated alkyl group of 3 to 6 carbon atoms, a straight-chain alkyl group of 2 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms, or a branched alkyl group of 3 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms, and X represents a nitro group or an amino group, provided that when X is a nitro group, R is neither an aralkyl group nor an ethyl group substituted by fluorine atom(s);
a process for preparing a nitrobenzene compound represented by the general formula (IV): ##STR3## wherein R' represents a branched alkyl group of 4 to 8 carbon atoms, a cycloalkyl group of 4 to 8 carbon atoms, an alkyl group of 1 to 3 carbon atoms having an alicyclic group of 3 to 7 carbon atoms, an alkyl group of 2 to 4 carbon atoms having an alkoxy group of 1 t 4 carbon atoms, an unsaturated alkyl group of 3 to 6 carbon atoms, a straightchain alkyl group of 2 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms, or a branched alkyl group of 3 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms, which comprises reacting a 3-nitrobenzyl chloride represented by the general formula (II): ##STR4## with an alcohol represented by the general formula (III): EQU R'OH (III) PA1 wherein R' is as defined above, in an aprotic polar solvent in the presence of an accepter of hydrogen chloride; and PA1 a process for producing an aniline compound represented by the general formula (V): ##STR5## wherein R represents a branched alkyl group of 4 to 8 carbon atoms, a cycloalkyl group of 4 to 8 carbon atoms, an alkyl group of 1 to 3 carbon atoms having an alicyclic group of 3 to 7 carbon atoms, an aralkyl group of 7 to 9 carbon atoms, an alkyl group of 7 to 9 carbon atoms, an alkyl group of 2 to 4 carbon atoms having an alkoxy group of 1 to 4 carbon atoms, an unsaturated alkyl group of 3 to 6 carbon atoms, a straight-chain alkyl group of 2 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms, or a branched alkyl group of 3 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms, which comprises reacting a 3-nitrobenzyl chloride represented by the general formula (II): ##STR6## with an alcohol represented by the following general formula (III'): EQU ROH (III') PA1 wherein R is as defined above, in an aprotic polar solvent in the presence of an accepter of hydrogen chloride, and reducing the thus obtained nitrobenzene compound.
A nitrobenzene compound represented by the general formula (IV'): ##STR7## wherein R.sup.1 represents a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group or an n-hexyl group, and an aniline compound represented by the general formula (V'): ##STR8## wherein R.sup.1 represents a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group or an n-hexyl group, are known.
For example, compounds represented by the formula (IV') and (V') wherein R.sup.1 is a methyl group are described in The Journal of the Chemical Society, vol. 1954 (1954) page 4127, in which a compound represented by the formula (IV') wherein R.sup.1 is a methyl group is synthesized at a yield of 72% by heating 3-nitrobenzyl chloride in a methanol dissolved metallic sodium therein, and a compound represented by the formula (V') wherein R.sup.1 is a methyl group is synthesized at a yield of 82% by reducing 1-(methoxymethyl)-3-nitrobenzene with iron-saline solution. The synthesis of compounds represented by the formula (IV') and (V') wherein R.sup.1 is an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group or an n-hexyl group are described in Chekoslovenska Farmacie, vol. 30 (1981) page 184, in which the compounds represented by the formula (IV') are synthesized at a yield of 65 to 75% in the same manner as in the synthesis of the compound represented by the formula (IV') wherein R.sup.1 is a methyl group, and the aniline compounds represented by the formula (V') are synthesized at a yield of 75 to 81% by reducing the corresponding nitrobenzene compounds.
As a compound having a branched alkyl group, a compound wherein R.sup.1 is an i-propyl group is known. U.S. Pat. No. 4,348,223 (1982) discloses a compound represented by the formula (IV') wherein R.sup.1 is an i-propyl group which is synthesized at a yield of 42% by heating 3-nitrobenzyl chloride with an aqueous solution of KOH in i-propanol and further a compound represented by the formula (V') wherein R.sup.1 is an i-propyl group which is synthesized at a yield of 91% by catalytic reduction of the corresponding nitrobenzene compound.
Many compounds are known in which R.sup.1 is a phenyl group. As a typical example, an unsubstituted phenyl group will be cited. By a process described in The Journal of the Chemical Society, vol. 1954 (1954) page 4573 a compound represented by the formula (IV') wherein R.sup.1 is a phenyl group is synthesized at a yield of 60% by heating 3-nitrobenzyl bromide and phenol in methylethyl ketone in the presence of K.sub.2 CO.sub.3, and the Journal of Pharmaceutical Sciences vol. 56 (1976) page 871 describes that a compound represented by the formula (V') wherein R.sup.1 is a phenyl group is synthesized at a yield of about 50% by catalytic reduction of the corresponding nitrobenzene derivative.
A compound represented by the formula (IV') wherein R.sup.1 is a benzyl group is described in The Journal of Organic Chemistry, vol. 51 (1986) page 2777 and a compound represented by the formula (IV') wherein R.sup.1 is a propynyl group (-CH.sub.2 C.tbd.CH) is described in Chemical Abstracts, vol. 83 No. 92302, but the detailed synthetic methods of those compounds are not described.
As a compound represented by the formula (IV') wherein R.sup.1 is a fluoroalkyl group a compound represented by the formula (IV') wherein R.sup.1 is a 2,2,2-trifluoroethyl group is known. A compound represented by the formula (IV') wherein R.sup.1 is a 2,2,2-trifluoroethyl group described in Analytical Chemistry, vol. 54 (1982) page 529 is obtained at a yield of 95% by reacting 2,2,2-trifluorodiazoethane (CF.sub.3 CH=N.sup.+ =N.sup.-) with 3-nitrobenzyl alcohol ##STR9## in fluoboric acid.
However, no prior publication discloses a compound represented by the formula (V) wherein R represents a branched alkyl group of 4 to 8 carbon atoms, a cycloalkyl group of 4 to 8 carbon atoms, an alkyl group of 1 to 3 carbon atoms having an alicyclic group of 3 to 7 carbon atoms, an aralkyl group of 7 to 9 carbon atoms, an alkyl group of 2 to 4 carbon atoms having an alkoxy group of 1 to 4 carbon atoms, an unsaturated alkyl group of 3 to 6 carbon atoms, or a straight-chain or branched alkyl group of 2 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms; or a compound represented by the formula (IV) wherein R' represents a branched alkyl group of 4 to 8 carbon atoms, a cycloalkyl group of 4 to 8 carbon atoms, an alkyl group of 1 to 3 carbon atoms having an alicyclic group of 3 to 7 carbon atoms, an alkyl group of 2 to 4 carbon atoms having an alkoxy group of 1 to 4 carbon atoms, an unsaturated alkyl group of 3 to 6 carbon atoms, or a straight-chain or branched alkyl group of 3 to 8 carbon atoms which has been substituted by 1 to 15 fluorine atoms.
As a result of the present inventors' various researches to provide a 1,2,4-triazole-3-carboxamide compound having an excellent weed killing effect, represented by the formula (VI): ##STR10## wherein R is as defined above, it has been found that a benzyl ether compound represented by the formula (I) is a useful compound as an intermediate compound of the 1,2,4-triazole-3-carboxamide compound represented by the formula (VI) as a herbicide, and on the basis of this finding, the present invention has been attained.